Limit analysis and design recommendations for fiber‐reinforced concrete subjected to shear

Abstract

AbstractIt is widely recognized in both research and practice that fibers have great potential to partially, or completely, substitute conventional transverse reinforcement in webs of girders subjected to moderate shear forces. However, despite extensive research in recent years, there is still no consensus in the research community on the mechanically sound modeling of the shear strength of fiber‐reinforced concrete (FRC). Accordingly, current code provisions for the design of FRC to resist shear rely on (semi‐)empirical approaches and are thus justifiably restrictive. This article addresses this knowledge gap by proposing the application of the theory of plasticity to the design of FRC webs. Limit analysis methods for conventionally reinforced concrete are extended to FRC by incorporating the residual crack‐bridging stress offered by the fibers in a consistent manner. This stress, as well as the limits of applicability of the theory of plasticity, are derived through a sensitivity analysis using the recently developed Cracked Membrane Model for FRC considering fixed, interlocking cracks. Based on these investigations, a straightforward and efficient mechanically based shear design model suitable for the design of FRC webs with and without conventional transverse bar reinforcement is proposed. The model is validated against a large database of panel and beam experiments, providing valuable insights into its reliability.